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In order to improve the seismic performance of adobe masonry, this paper proposes a recycled adobe brick reinforced masonry structure. Four specimens are designed and fabricated for quasi-static tests. The influence of core column and horizontal steel bar on the seismic performance of recycled adobe brick masonry is studied by analyzing the failure mode, hysteresis characteristics, stiffness and strength degradation, bearing and deformation ability, energy dissipation and steel strain of the specimens. The test results show that the setting of both ending core columns could effectively improve the seismic performance, including seismic shear bearing capacity, ultimate deformation, lateral stiffness, energy dissipation and so forth. The ultimate deformation of recycled adobe brick masonry with both ending core columns is upgraded by 42.8 %, compared to that of unreinforced masonry in particular. When recycled adobe brick masonry with both ending core columns is further reinforced with middle core column, the seismic shear bearing capacity and energy dissipation of which is improved by 46.8 %, 176.2 % compared to those of that of unreinforced masonry respectively. Besides, when specimen reinforced with both ending core columns and horizontal steel bars, the seismic shear bearing capacity and energy dissipation of which is improved by 46.5 %, 261.6 % compared to those of that of unreinforced masonry respectively. Finally, the calculation formula of seismic shear bearing capacity of recycled adobe brick reinforced masonry is put forward through the theoretical analysis and analysis of test results. • A kind of recycled adobe brick which consumes waste brick and has good mechanical properties is proposed. • Recycled adobe brick reinforced masonry solves the problem of poor seismic performance of adobe brick masonry. • The core columns and horizontal steel bars significantly improve the seismic performance of the wall. • The calculation formula of shear capacity of recycled adobe brick reinforced masonry is proposed. [ABSTRACT FROM AUTHOR]

As one of the earthwork building methods, the adobe masonry has a long history around the world. In 2015, the Zhengzhou Institute of Cultural Relics and Archaeology discovered the earliest adobe house in Prehistoric China at the Qingtai Site. In this work, physical properties, material composition, and microstructure of the adobe brick and other earth samples gathered in this adobe house were studied. The results showed that the density and surface hardness of the adobe brick reached 2.12 g/cm and 91 HA, which was second only to the rammed house floor sample. The adobe brick contained about 13.2% of plant fiber, and in its inorganic composition, the clay cement with particle size less than 0.075 mm accounted for 90%. The results of XRD analysis showed that the content of kaolinite in adobe brick was 2–5 times that of other samples. The structure analysis displayed that the adobe brick was much more compact, and its porosity was about 28.6%. These research results demonstrated that the adobe brick was formed under a certain pressure and its raw materials were different from those of other samples in this adobe house. [ABSTRACT FROM AUTHOR]

In this study, some physical properties of Lefke (Bilecik), Keşan (Edirne), Çan (Çanakkale) and Küfeki (Istanbul) stones, which are used as building materials in their regions, were investigated. Samples were taken from two separate quarries for each stone, and after chemical analysis, thermal conductivity, compressive strength, water absorption, respiration ability and abrasion tests were performed. As a result of the tests, it has been revealed that i) Çan, Tüfekî and Lefke stones, among the ones examined, with low thermal conductivity coefficient values (0.342 W/mK, 0.564, 0.860 W/mK), can be used as briquettes, bricks or wall covering materials for thermal insulation and decoration purposes, ii) Keşan stone can be used in load-bearing wall material and wear-resistant flooring with 81.3 MPa compressive stress and 4.83% wear rate values and iii) four stones have rich reserves and low costs. The results were compared with other building materials especially in terms of energy saving, strength and comfort conditions. [ABSTRACT FROM AUTHOR]

The aim of this study is to examine the effects of cement stabilization on the mechanical stress of compressed stabilized earth blocks (CSEBs) and adobe stabilized earth bricks (ASEBs). Hence, this work is based on an experimental study carried out in order to determine the geotechnical properties of the samples soil, namely, the dry particle size analysis after washing, the particle size distribution by sedimentometry, Atterberg limits, and the preparation of specimens with different levels of cement proportions. Moreover, single compression and three-point bending compression out on specimens measuring 4x4x4cm3 and 4x4x16cm3 respectively. The findings indicate that dosing with 8% cement results in a clear increase in compression stress of approximately 25.55% for CSEBs compared to the reference set at 0% and 22.85% for ASEBs. On the other hand, for a dosage of 4%, we observe a slight increase in stress by simple compression of around 3.26% for CSEBs and 3.14% for ASEBs. For three-point bending compression for a cement dosage of 8%, there is also an increase in stress of about 25% for the CSEBs compared to the reference taken at 0% and 23.02% for the ASEBs. [ABSTRACT FROM AUTHOR]

Iran is one of the oldest countries in the world, benefiting from adobe-based architecture. The present study investigates the effect of dynamic compaction on mechanical properties of adobes using clayey-silty soils from Ardakan city, Yazd, Iran, with a focus on the compressive, tensile and flexural strengths in relation with the particle size distribution of the earth. However, it is found that the results of this mechanical stabilization are in function of the mineralogical compositions as well. In this regard, adobe samples in the control and experimental (compacted) groups were made with six soil types of six different mines, and their physical, mineralogical, and chemical characteristics were determined. Compressive, tensile, and flexural strengths of samples were examined, and the mechanical strength of the unbaked adobe bricks was correlated with the physical properties of the soils. The laboratory studies confirmed the direct relationship between dynamic compaction and mechanical strength. The results showed that soil compaction in the experimental adobes results in an increase of compressive strength by 79.43 %, tensile strength by 42.42 %, and flexural strength by 75.00 % compared to control adobes which lacks compaction. So, dynamic compaction is an acceptable method for manufacturing earthen materials such as adobe according to the required standards.

Adobe bricks are extensively used for the construction of adobe houses. The lack of strength is one drawback of these bricks; therefore the soil used to build these bricks is stabilized with several natural stabilizers. This study conducted to­­­ compare the effects of commonly used stabilizers, which are straw and rice husk on the compressive strength and tensile strength of adobe. Study provided the experimental data and the analyzed failure pattern of the stabilized and un-stabilized specimens subjected to unconfined compressive strength test and splitting test. From the obtained results, the increase in compressive strength, decrease in tensile strength, increase in the elasticity under compressive loads and no major failure under compression and tension was observed for the specimens containing stabilizers. Results revealed the maximum positive effects of straw than rice husk in improving the adobe’s resistance to the compressive and tensile loads.

To achieve net-zero carbon emissions in a building's lifecycle, a comprehensive approach is required, addressing both embodied and operational carbon footprints. To support this goal, this study assesses the environmental, hygrothermal, and mechanical characteristics of different carbon-free adobe bricks bio-sourced with straw and evaluates their impacts on improving the energy performance of a one-story case study building located in a semi-arid climate. At the material scale, the mechanical performance, hydrothermal behavior, and durability of carbon-free straw-reinforced adobes, with weight percentages of 0, 1, 2, 3, and 4%, at different sizes: long straw (100–200 mm) and crushed straw (5–25 mm) were studied. The results show that incorporating straw into bricks increases porosity, enabling the production of lightweight bricks that comply with Moroccan standards for lightweight structures, possessing a density lower than the accepted limit of 1750 kg/m³. Furthermore, the thermomechanical properties of reinforced adobes were considerably improved compared to non-reinforced ones, with a gain in mechanical compressive and flexural strengths of 31.2% and 184%, respectively. However, it is important to note that in the case of adobe bricks reinforced with long straw (BLS), the findings revealed that, unlike other thermomechanical properties, long straw has a negative effect on compressive strength. Additionally, thermal conductivity decreased by 93.8% and 86.8% for a 4% inclusion of long and crushed straw, respectively. At the building scale, the indoor hygrothermal comfort was evaluated with respect the hot, semi-arid region in southern Morocco. The results show that the reinforced adobe material is able to reduce the indoor temperature of the case study building from 3 °C to 12 °C during the summer time, compared to the outdoor temperature, with a time lag of up to 5 h between the interior and exterior. Moreover, it successfully maintained diurnal indoor air temperature fluctuation within 2 °C. In addition, indoor relative humidity remained in the recommended 40%–65% by ASHRAE Standard 62.1–2022, over 78% during the monitoring period, even when the outside relative humidity fluctuated significantly (5–95%). Finally, a Morris-based sensitivity analysis was carried out on nine design parameters of the case-study building to assess the impact of varying the thermal properties of reinforced adobe bricks on cooling and heating energy performance, respectively. Thermal conductivity was found to have a significant impact on cooling energy demands and a lesser influence on heating demands. The study also indicates that straw-reinforced adobe bricks can improve cooling energy performance by up to 17.8% without compromising the overall embodied carbon of the building envelope. [Display omitted] • X-ray diffraction and MEB-EDS characterization of the extracted clay sample. • Physical, thermal and mechanical properties of adobes are studied. • Adobes reinforced with long straw show higher porosity than those with crushed straw. • Energy model validation with primary data from an existing Moroccan building. • Design parameters' impact on thermal energy using Morris's sensitivity analysis. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Pine needle can be used as vegetable fibre for adobe bricks. • Mechanical performance of adobe bricks is defined by the pine needle ductility. • Fibres pn1 and pn2 show better mechanical behaviour than pn3. • Adobe brick with pn1 shows high kinematic ductility. • Adobe brick with pn1 shows the best elasto-plastic behaviour. Abstract Different types of vegetable fibres are used in the manufacture of adobe bricks to control the cracking during the drying process. In Spain, and in many other countries of the world, the fibre commonly used in the manufacture of adobe bricks is cereal straw, usually wheat. The purpose of this research is to determine the behaviour of three types of pine needles as a vegetable fibre in the adobe mass: Pinus halepensis (pn1), pinea (pn2) and pinaster (pn3), all of them abundant in the Iberian Peninsula. The results obtained show their viability, providing high resistance and ductility to the adobe. [ABSTRACT FROM AUTHOR]

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Adobe is an ancient building technology made of sun dried bricks joined together by mud mortar. This paper deals with the physical and mechanical characterization of three different typologies of adobe bricks and one typology of mud mortar produced in Europe. They differed in terms of internal soil element proportions and amount of organic content. Physical tests consisted of granulometry, moisture content and density tests. The mechanical characterization consisted of uniaxial compressive tests and three point bending tests. Tests were performed according to modern material standards. The main mechanical properties both in tension and compression were determined at different curing conditions. The outcome provided in this study offers a general overview on the assessment of the mechanical performance of adobe in relation to the properties and interactions of its soil constituents. In fact, the comparison between components with the same soil mineralogical family and production process made it possible to assess both at a qualitative and quantitative level the effect of the physical properties of the mixture (such as fiber and clay percentages or moisture content) on the mechanical parameters of the resulting bricks and mortar. This paper proposes new predictive formulations of the most relevant material parameters in strength and deformation, such as compressive strength, deformation at peak stress and ultimate displacement for both adobe bricks and mortar. They quantify the influence that water content, clay percentage and fiber reinforcement produce on the mechanical performance of the tested adobe components. This was made possible by means of multivariate statistical analyses on the mechanical parameters derived from all the tested samples. [ABSTRACT FROM AUTHOR]

The main problem with clay-based surfaces is the reduced resistance to water action. Literature does not indicate scientifically validated solutions for surface treatment. However, there are reports that indicate the benefits of impregnating surfaces with animal oils, vegetable oils, petroleum products, etc. The aim of this paper is to identify a solution for treating the surface of earth made bricks, in order to increase the degree of waterproofing and the resistance to water action, using local materials, specific to the western part of Romania. To achieve this, was used a surface treatment based on marble, lime, sand, clay, and water permeation reducing additive. On clay surfaces treated with this material, water vapor permeability and water penetration under wind pressure tests were conducted. The experimental results obtained indicated the optimal composition for the surface treatment material so that it does not crack upon drying, have good adhesion to the substrate, and improve substrate resistance to water action. [ABSTRACT FROM AUTHOR]

In the sustainable development context, the possibility of recycling, reuse and reintegration in nature, environmental protection and efficient management of natural resources are significant indicators. Adobe bricks type masonry units meet successfully these requirements. This paper presents a series of experimental research conducted to explore the clay material recycling possibility of the adobe bricks type masonry units, previously used for various purposes. The used testing methods were chosen so as to pursue the preservation or not of some essential physical and mechanical characteristics (mechanical strength, density, axial shrinkage, thermal conductivity). The results indicated the followed parameters preservation for the specimens performed from recycled clay, compared to similar specimens, in whose composition has not been introduced recycled material. Also, the experimental results have indicated the reinforcing possibility with vegetable fiber (straw or hemp fibers), even if the binder was made using the recycled clay. [ABSTRACT FROM AUTHOR]

This study is focused on quantifying the amorphous phases in soil-related material samples by quantitative phase analysis (QPA) with a carefully designed methodological strategy in the X-ray diffraction sample measurement and in the refinement procedure. The configuration applied was Debye-Scherrer geometry with Mo Kα radiation which, together with meticulous instrumental profile modelling using an LaB6 standard, allowed the refinement of a minimum of sample-related parameters. This method was applied to two micro-samples of adobe earth bricks from The Great Pyramid of Cholula, Mexico, and one local soil micro-sample containing several amorphous and semi-crystalline phases such as allophane, volcanic glass and opal. The results obtained by the QPA method, complemented by elemental particle induced X ray emission (PIXE) spectrometry analysis, were compared with a silicon chemical environment analysis by 29Si MAS-NMR. An average amorphous content of 40 wt% was calculated with the QPA/PIXE results, which is in agreement within 10% with the NMR experiments. Consequently, the methodology proposed could be of interest for further studies of cultural heritage geomaterials, which usually contain amorphous phases in their composition and allow only micro-sampling. [ABSTRACT FROM AUTHOR]

Sustainability is a criterion defined in the 80, which is essential in all fields of current activity. At the moment, it can not talk about development without being taken into account sustainability criteria. It presents the ensuring for an harmonious development, in line with current needs, without to endanger the possibility to develop and satisfy the needs of future generations. The buildings of adobe bricks-type elements ensure successfully the conditions imposed by this criterion. This type of construction ensures the responsible use of renewable natural resources, the possibility of reuse and recycling of materials, contributes to environmental protection and to pollution reduction, to energy saving and it provides a cleaner and healthier living environment. Not least, the buildings of this type are accessible in terms of cost and can contribute to the development of other fields such as eco-tourism. [ABSTRACT FROM AUTHOR]

This article describes the challenges and initial accomplishments of a project developed by the Pontifical Catholic University of Peru (PUCP) to disseminate technology and to train low-income families in the Andes Mountain region to build earthquake-resistant homes made of adobe bricks. The initiative has focused on improving the livability of households through affordable seismic reinforcement of traditional construction processes to enhance the social sustainability of housing in the area. We selected the rural Andean community of Pullo as a case study because of its preponderance of non-reinforced adobe construction and poverty. The research team developed tools and methodologies for technology transfer, worked with local residents to raise awareness of the high seismic vulnerability of adobe dwellings, and introduced the concept of seismic reinforcement. This article explores the barriers to disseminating earthquake-resistant technology in the study area and presents adaptive measures to overcome these challenges. Initial results demonstrate the positive impact of educational workshops to raise seismic awareness and to introduce earthquake-resistant construction among rural dwellers. The project is deemed to have wider applicability to other communities in seismic areas with similar housing, social, and economic conditions. [ABSTRACT FROM AUTHOR]

Consistent access to clean water is amongst the most pressing of global crises, particularly in less developed and off-grid communities. We present a high-efficiency solar evaporation device perfectly suited to address this crisis. Composed solely of soil, the adobe brick is a material that is easy to fabricate, and whose raw constituents are widely available at no cost. Once prepared, these bricks exhibit superb water absorption properties, excellent solar absorption, and efficient photothermal conversion, all of which contribute to a pure water evaporation rate of 2.52 kg m−2 h−1 (77 % evaporation efficiency) and a salt water evaporation rate of 2.16 kg m−2 h−1 under an irradiance of one sun. Suitable pore sizes allow salt water to be converted to fresh water with only minimal salt buildup over 6 h and rapid rejection of particulates to the reservoir below. Variations in soil makeup and inclusion materials are characterized in detail, and evaporation rates are compared. This enables recommendations for the composition of an ideal adobe brick evaporator and important conclusions for the study of solar evaporation materials. While soil composition may be optimized for performance, the high evaporation rates of all samples indicate opportunities for adobe brick desalination across all biomes. • Baked adobe bricks, composed solely of soil, are demonstrated as solar evaporators. • The impacts of soil composition, inclusions, and porous structure are studied. • An excellent evaporation rate of 2.52 kg m−2 h−1 is achieved under 1 sun. • The natural porous structures of the bricks enable effective salt rejection. • Simple, low-cost fabrication facilitates use for particularly water-scarce regions. [ABSTRACT FROM AUTHOR]

Background: The adobe bricks of old buildings can preserve diaspores of cultivated and weed species associated with arable fields. Recovery of these plant remains can provide insight into historical agriculture, and former weed flora. Aims: This study aims to describe and evaluate the changes in the weed flora in south-western Hungary, based on archaeobotanical findings and contemporary plot surveys. Methods: Plant remains of 51 adobe bricks dating from 1850 to 1950 were identified in south-western Hungary and compared with the flora of 104 plots from the same region. Results: A total of 276 species were identified from the adobe bricks, while the present-day plot survey yielded 305 species. A significant difference was found between the historical (60- to 160-year-old) and current species richness of the weed flora. The proportion of rare and threatened species decreased by 38.1%. A total of 142 weed species identified from the adobe bricks have declined, and 40 of them even disappeared in comparison with the contemporary surveys. Today, in Hungary and neighbouring countries, more than 80 of these species are rare or threatened and some of them are extinct or critically endangered. Conclusions: Our findings show that many weed species that flourished in the early twentieth century have declined. This is most likely due to the intensive management practices of cultivated fields and the spread of invasive neophyte taxa. We showed that analysing the botanical information preserved in adobe bricks is a reliable method that can provide evidence of long-term changes in weed flora. [ABSTRACT FROM PUBLISHER]

The domestic architecture in the rural villages of İzmir comprises a unique built environment with their masonry wall textures, semi-open sofas, round tiled-hipped roofs, and chimneys, and represents an important part of the cultural and architectural heritage. This assessment is mainly based on field observations that focus on the architectural and structural layout of intact, damaged, and destroyed houses. During field observation and the analysis of data certain plan typologies and relationships between the geological formations of the region and choice of materials and construction techniques were observed. While load-bearing masonry and timber skeleton systems are common, extensive use of timber laces, stone, and fired or adobe brick masonry with mud mortar and timber frames infilled with masonry materials were frequently seen. Generally, round timber elements such as wall plates, laces, lintels, posts, and frames of flooring systems are used. Architectural degenerations in authentic houses, defective details and partially due to the earthquake-prone nature of the region seismicity have been evaluated. An overall approach for the preservation and sustainability of this heritage is suggested. [ABSTRACT FROM PUBLISHER]

Adobe buildings are located in many countries and are often constructed with fiber reinforced bricks, which are composite materials made of soil, water, and natural or artificial fibers. This study presents experimental findings for straw fiber reinforced adobe bricks typically used in Sardinia (Italy) and produced according to traditional worldwide handcrafted manufacturing procedures. A large number of compression and three-point bending tests were carried out on cubic and prismatic specimens, respectively. The identification of significant scatter in experimental data sets due to handcrafted manufacturing motivated the estimation of mechanical parameters at different percentile levels, in order to provide their characteristic and median values. The geometry of straw fibers was statistically characterized in terms of mean, standard deviation and probability distribution of their diameter and length. The mechanical characterization in compression included the estimation of fracture energy. Bending test data were processed to estimate Young’s modulus in tension, highlighting the bimodularity of the earthen composite material. Finally, both elastic–perfectly plastic and nonlinear stress–strain models are proposed for design/assessment purposes. [ABSTRACT FROM AUTHOR]

Huancavelica, Peru, a historic cinnabar refining site, is one of the most mercury (Hg)-contaminated urban areas in the world. Exposure is amplified because residents build their adobe brick homes from contaminated soil. The objectives of this study were to compare two Hg-leaching procedures, and their application as risk-assessment screening tools in Hg-contaminated adobe brick homes in Huancavelica. The purpose was to evaluate potential health implications, particularly for children, after ingestion of Hg-contaminated particles. Hg was measured in adobe brick and dirt floor samples from 60 households by total Hg extraction, simulated gastric fluid (GF) extraction, and sequential selective extraction (SSE), which provides more detailed data but is resource-intensive. Most of the Hg present in samples was relatively insoluble, although in some households soluble Hg species were present at concentrations that may be of concern after ingestion. A strong correlation was identified between results from simulated GF extraction of adobe bricks and dirt floors and the more soluble fractions of Hg from SSE. Simulated GF extraction data were combined with ingestion and body mass characteristics for small children to compare potential risk of ingestion of Hg-contaminated soil with current health standards. Simulated GF extraction can be used as a risk assessment screening tool for effective allocation of time and resources to households that have measurable concentrations of bioaccessible Hg. Combining simulated GF extraction data with health standards enables intervention strategies targeted at households with the greatest potential health threat from ingestion of Hg-contaminated particles. [ABSTRACT FROM AUTHOR]

Clayey soil type has been used for constructions since ancient times. Starting with the 90s, there have been research regarding the use of sandy clay as material for creating secure and sustainable structures, which would provide thermal comfort. This paper work presents the experimental results regarding the possibility of improving certain physical and mechanical characteristics by introducing in the mixture certain fillers (sand, bone glue, lime paste, hemp fibers, straw), each having a well determined role, sand being essential. The experimental results have shown that the admixture containing hemp fibers is more suited for making the masonry elements that are subject to flexural stresses and the straw one is more suited for thermal insulation. [ABSTRACT FROM AUTHOR]

This paper shows some results of the analysis of wall construction with adobe bricks, carried out in a pilot building in Villa Clara, Cuba. Our main objective was to obtain some construction recommendations to avoid the humidity due to capillarity. The recommendations deal with uprising speed of construction, adequate wall longitude, binding mortar between adobe bricks, adobe protection from weathering, etc. [ABSTRACT FROM AUTHOR]

Adobe is one of the oldest construction materials that is still used in many seismic countries, and different construction techniques are found around the world. The adobe material is characterized as a brittle material; it has acceptable compression strength but it has poor performance under tensile and shear loading conditions. Numerical modelling is an alternative approach for studying the nonlinear behaviour of masonry structures such as adobe. The lack of a comprehensive experimental database on the adobe material properties motivated the study developed here. A set of a reference material parameters for the adobe were obtained from a calibration of numerical models based on a quasi-static cyclic in-plane test on full-scale adobe wall representative of the typical Peruvian adobe constructions. The numerical modelling, within the micro and macro modelling approach, lead to a good prediction of the in-plane seismic capacity and of the damage evolution in the adobe wall considered. [ABSTRACT FROM AUTHOR]

Excavations at the site of Cerro Portezuelo, located on the lower slopes of a hill in Chimalhuacan, State of México, were begun by George Brainerd in 1954 and continued in 1955, but he died suddenly, before a projected third season could take place. With the exception of a few small structures higher on the hill, no signs of significant structures were visible on the surface. Architectural features revealed through excavation, however, included a platform with associated caches of the Middle Classic period, a platform and a burial area of the Epiclassic period, and a residential complex that appears to have spanned the Early and Late Postclassic periods. This complex included a sunken patio, a freestanding shrine, habitational rooms, and other features. Construction materials included stone, adobe brick, and tepetate. [ABSTRACT FROM PUBLISHER]

Abstract: A study of the influence of testing procedures in the mechanical characterization of adobe bricks traditionally used in Aveiro district, Portugal, was conducted. Cylindrical and cubic adobe specimens were subjected to simple compression tests, adobe bricks to flexural tests, and cylindrical adobe specimens to splitting tests. With these tests it was possible: (i) to collect more data to improve the knowledge of the mechanical behavior of adobe; (ii) to determine correlations between results obtained with different testing procedures; and (iii) to perform a rigorous characterization of the deformations suffered by adobe under compression, by measuring deformations directly on test specimens. [Copyright &y& Elsevier]

Abstract: The present paper deals with the in situ mechanical characterization of 2000years old adobe bricks from the archaeological site of Nisa Partica in Turkmenistan. For this purpose, a portable instrument was designed to perform compression, three point bending, and ‘Brazilian’ tests. This simple instrument allowed in situ measurement of compressive and tensile strengths of the material, providing stress–strain curves that have been used to calibrate simple constitutive relationships. Finally, bricks were mineralogically and petrographically characterized. The paper shows that with simple tools it is possible to measure the main mechanical properties of adobe bricks even in critical in situ conditions. [Copyright &y& Elsevier]

A mud brick functions as an element of masonry structures. Being an integral part of a wall mass, it must be understood structurally and chemically. The susceptibility of a mud brick to be affected by decay agents depends on the type of raw materials used, the methods of construction, location, the microclimatic conditions, the mechanical and microstructural characteristics of the mud brick itself. In this research, mineralogical composition and granulometric distribution of ancient mud bricks were studied by using some scientific techniques such as XRD, SEM and electrical mechanical sieves, to determine the main components and characteristics, which will serve as reference for the contrivance of new mud bricks. In addition, special knowledge of the physical properties of historic mud bricks were defined by some scientific techniques to get some information about their properties, such as density, porosity, water absorption and shrinkage. Furthermore, all of those characteristics were studied in two groups of new mud bricks, to determine their properties. Finally, our results proved that the 6th category in the 1st group and the 10th category in the 2nd group are the most appropriate types for restoring and preserving the studied monument, due to their good physical properties, morphological appearances and their suitable characteristics. [ABSTRACT FROM AUTHOR]

Abstract: A study of the mechanical properties of adobe bricks collected from houses and land dividing walls in Aveiro district, Portugal, representative of existing traditional constructions, was conducted. Cylindrical adobe specimens were subjected to simple compression and splitting tests. From these tests it was possible to evaluate the strength capacity, stiffness and deformation evolution for increasing loading. Correlations between the evaluated properties were determined, and the results obtained for houses and land dividing walls were compared. This study contributes for the characterization of adobes traditionally used in Aveiro district, and provides reference values that can be considered in rehabilitation processes. [Copyright &y& Elsevier]

Adobe is a construction technique that uses raw clayey earth mixed and moulded to form blocks to realize a bearing wall. Romans were also used to add sand or coarse sand into the mixture to “degrease” clay and to allow to make it into a mixture. Fibres such as straw were often added into the mixture. Anyway, ancient home brick-makers have not had a chance to do scientific experimental investigation on the balance of ingredients and the optimisation of this production. This paper elaborates on how workability and mechanical properties of Roman ancient adobe earthen bricks change by varying the percentage of an on situ soil, straw and coarse sand into the mixture to produce them. The comparisons were also made with the only-earth samples. Breaking manners of all the samples were also compared. [Copyright &y& Elsevier]

Abstract: This study presents the development and characterisation of transparent sol–gel TiO2 coatings based on titanium IV isopropoxide (TIP4), formed on a sustainable clay brick material (adobe). The sol–gel layers modified the surface of adobe, which can potentially lead to new functionalities enhancing adobe performance, e.g. higher water resistance and imparting bactericidal behaviour. X-ray diffraction results on synthesised TiO2 layers based on TIP4 showed that the film has characteristic peaks of anatase phase. Static SIMS analysis was used to detect the presence of TiO2 on adobe surfaces, which were also observed by TEM confirming their thickness to be in the range 20–50nm. Sol–gel double SiO2–TiO2 layers were also deposited on adobe substrates. These coatings did not exhibit any cracks neither signs of peeling off from the substrate. The developed surface modified adobe bricks are attractive sustainable building materials. [Copyright &y& Elsevier]